Various forms of aerobic exercise are intended to develop different parts of the body. The above noted parent applications and patents disclose different forms of steps which could be used to supplement an aerobic exercise by permitting the user to step up and down from a horizontal platform to the floor. In general, the steps of the above parent patents and applications include some form of adjustability to permit the exercise program to conform to the particular individuals. This is generally accomplished by providing height adjustability so that a selective number of different heights can be provided for the platform. Parent U.S. Pat. No. 5,162,028 also provides for width adjustability in addition to height adjustability. In all of these approaches, however, the adjustability is intended to provide a single level step. It would be desirable if an exercise step could also be provided which permits the user to have multiple height levels during the same exercise program.